Specific fixtures are required in woodwork to firmly clamp a workpiece in place, so that accurate, quick, and convenient drilling and groove-milling works may be performed on the workpiece at desired positions. FIG. 1 is a cross sectional view of a conventional base frame for fixture disclosed in U.S. Pat. No. 6,622,997 B2. The conventional base frame for fixture in FIG. 1 is an extruded member having integrally formed upper channel A and lower channel B. A fixture C is inserted in and engaged with the lower channel B, so as to firmly hold a workpiece in place; and a drill rest E is engaged with the upper channel A via connecting brackets D, so that drilling works may be performed. With the above-described structure, the conventional base frame for fixture of FIG. 1 may only clamp the workpiece in a simple manner to perform only the drilling work, and does not have the groove-milling or other function. The conventional base frame for fixture shown in FIG. 1 is therefore not very ideal for woodwork. It is therefore tried by the inventor to develop an improved base frame for fixture that is multi-functional and more convenient for use as compared with the conventional product.